Quality Components And Genetic Diversity Analysis Of Dioscorea Polystachya Turcz.

Dioscorea polystachya Turcz. is a grain, vegetables, feed, medicine and power source plant. It has great application prospects in the resources development of food, starch, feed, medicine and biology. It is also an efficient cash crop with characteristic industry development potential. the Dioscorea polystachya Turcz. in Fujian still exist many problems, such as variety aging, sexual degradation, name confusion, uneven quality, and lower level of industrialization. Therefore, the investigation on the resources of Dioscorea polystachya Turcz. in Fujian is necessary, and of great value for the production, introduction, breeding, and resources access of the Dioscorea polystachya Turcz.. In this thesis, basing on the analysis of morphology diversity, the genetic diversity of Dioscorea polystachya Turcz. is systematically investigated using RAPD-PCR technique in DNA level. Moreover, the quality of representative Dioscorea polystachya Turcz. is also analyzed and assessed. The major results and findings are as follows:1,Research on morphological diversity The biological traits of 15 types are studied using clustering analysis method, the dendrogram of genetic distance is also constructed. It is found that as the absolute distance is in the range of 13~26, the 34 Dioscorea polystachya Turcz. resources from Fujian can be divided into two broad categories according to the intensity of the growth vigour of the over-ground part. When the absolute distance is in the range of 9~13, the category with weak growth vigour can be classified into two subcategories. One of the subcategories is elongated Dioscorea polystachya Turcz. with brown skin, besides, the tuber has branches. The other subcategory is bar Dioscorea polystachya Turcz. and big tuber. Furthermore, as the absolute distance is about 8, the bar Dioscorea polystachya Turcz. and big tuber can be differentiable.2,Research on genetic diversity by RAPD The genetic diversities of 34 Dioscorea polystachya Turcz. in Fujian province are investigated using Random amplified polymorphic DNA (RAPD) technology. 24 Primers are selected from 243 random RAPD primers, and then used to amplify the 34 Dioscorea polystachya Turcz. respectively. The amount of the amplification bands is 182, in which the polymorphisms account for 88.5%. The genetic distance coefficients of the different bands are analyzed using statistical data software DPS. Then the matrix of genetic distance coefficients is constructed. Finally, the diagram of clustering analysis is obtained by the UPGMA method, which is used to analyze the 34 Dioscorea polystachya Turcz. resources. The results show that when the genetic similarity coeffiicient iss 0.66, the 34 resources could be divided into 4 classes: D. batatas Decne, D. alata L, flat D. batatas Decne and Sanming D. alata L. When the genetic similarity coeffiicient is 0.68, D. batatas Decne could be divided into two subcategories: elongated Dioscorea and bar Dioscorea. Our results agree with the classical horticulture, and Supports the view of the horticulture classification of Dioscorea polystachya Turcz at the molecular level.3,Research on quality analysis The moisture contents of Dioscorea polystachya Turcz.resources are measured. It is observed that the moisture content of bar Dioscorea polystachya Turcz. is the highest with the ratio more than 80%, the latter one is the Dioscorea polystachya Turcz. of yellow-brown skin, the moisture content of which is higher than the big tuber, the bar Dioscorea polystachya Turcz. with the brown skin has the lowest moisture content, the lowest dioscin content 67.27%. In addition, the dioscin and allantoin of the Dioscorea polystachya Turcz.are also measured using HPLC. The results show that the contents of dioscin and allantoin are quite different for the different Dioscorea polystachya Turcz.. The Dioscorea polystachya Turcz. with the highest dioscin content is Nanping 2#, whcih reaches as much as 91.54 ug/g. However, the sample from Jianning is of the lowest dioscin content 58.40 ug/g. Similarly, the content of allantoin is also considerably different from each other. In detail, Yongan 2# has the highest content (2.03%) while the Jiangle 3# has the lowest content, which is only 0.16%. According to our research, the bar Dioscorea polystachya Turcz. are of the higher allantoin content. Moreover, the soluble sugar, starch, as well as polyphenol content are also measured using spectrophotometry. The results are as follows: The sugar contents of Jiangle 3# and Zhenghe 3# are 17.19 ug/g and 3.01 ug/g, respectively. The highest starch content is the sample from Fuzhou, the minimum one is the Jiangle 1#. Moreover, they are 241.32μg / g and 1036.33μg / g, respectively. Generally speaking, the big tuber has the highest starch content. It is noticed that the soluble sugar and starch content are in no correlation; The sample of Zhenghe 1# is of the highest polyphenol content, and the ratio reaches 2.62%, while the minimum one is Yongle 3#, the polyphenol content of which is only 0.36%. The soluble proteins of the Dioscorea polystachya Turcz. are determined quantitatively by the Bradford method. The results show that the content of the soluble protein of the Dioscorea polystachya Turcz. from Fuzhou is the highest with 22.17 mg/g, while the lowest one is the Zhenghe 1#, the content of which is only 4.39 mg/g.